Boys lie because girls fall in love with what they hear.
Boys say girls are complicated and girls say boys are complicated when the truth is we are BOTH very complicated.
For example when a guy tells you you're beautiful and you say "Oh stop I know I'm not" or "No I'm not you have to say that you're my boyfriend". He doesn't really have to say anything he just does it because he does really think you're beautiful and clearly you're just saying that you're not so that he keeps telling you you're beautiful
Or... When boys will say anything to a girl just to get her to do stuff with him like hello have some manners maybe be an actual gentleman and you will get a great girl. We both lie and we both play mind tricks to get each other to do and say certain things that will be good for both of our egos. So why pretend like we don't?